1. Field of the Invention
The present invention relates to an egg yolk extender composition and egg yolk replacer as well as egg compositions prepared using the same.
2. Description of the Prior Art
Egg yolk extenders and replacers are well known in the art. They generally comprise various materials of grain or dairy origin in combination with various gums and emulsifiers. It is taught in U.S. Pat. No. 1,762,077, issued June 3, 1930 that lecithin emulsified with food fat can replace egg yolks. Egg yolks can be extended up to 50% by the use of equal parts of egg yolk and lecithin emulsified with twice the amount of water (1 part lecithin-2 parts water) as is disclosed in British Pat. No. 392,789, accepted May 25, 1933. Alien Property Custodian, 274,000 to Kramers, published May 4, 1943 discloses an egg substitute of casein, lecithin, fatty oils and optionally, a gum. However, it was found in Germany during World War II, that soybean lecithin cannot fully replace egg yolk in baked goods (Kirk-Othmer Encyclopedia of Chemical Technology, 2nd Edition, 1965, Vol. 12, page 356). In addition, most bakers prefer not to use lecithin as it is sticky and difficult to handle.
Egg yolks have also been extended for use in some areas by full fat soy flour. The main problem with the use of full fat soy flour is the inability of the baker to replace the egg yolk in his recipe on an equal weight basis without modification of the recipe. Full fat soy flour is unusable as a general egg yolk extender.
Generally, use of egg yolk extenders requires a modification of the recipe to obtain the required functional replacement of the egg yolk. The egg yolk extender should provide the emulsification and water binding characteristics of the egg yolk replaced. If the water binding characteristics are different from egg yolk, the baker's recipe will require modification in the amount of liquid added.
Since egg yolk provides various functions, one or more of which may be required in any specific recipe, the formulation of a general egg yolk extender requires consideration of all the areas in which egg yolk is useful and the functions which it performs in those areas. Most known egg yolk extenders do not provide the generality of use desirable. Thus, the use of some egg yolk extenders is limited. It would be commercially desirable to provide an egg yolk extender which can be used to replace egg yolk on an equal weight and functional basis without the need for modifying the recipe with regard to critical aspects such the water content.
These problems have been overcome with a formulated composition as disclosed in applicant's copending application Ser. No. 677,354, filed Apr. 15, 1976, now U.S. Pat. No. 4,072,764 which discloses an egg yolk extender composition comprising full fat soy flour, a grain flour, lecithin, humectant, a food grade emulsifier other than lecithin, a food grade gum and an appearance agent. It is taught that this composition can effectively extend egg yolks functionally on a 1:1 by weight replacement basis.
At the time of filing that application, full fat soy flour was an item of commerce, easily obtainable at a relatively low cost. Since that time, all local producers have either ceased manufacture or make it available at a cost which is prohibitive in preparing an egg yolk replacer which is more economical to use than natural egg yolks. The full fat soy flour is still available from Europe but the shipping charges make the cost prohibitive.
To fill the gap left by the removal of full fat soy flour, manufacturers are now selling a refatted soy flour. Soy oil and a small amount of lecithin which is also removed in the defatting process are blended with defatted soy flour to form the product. The final product has a lipid content of about 16% whereas the full fat soy flour has a lipid content of about 22%. Refatted soy flour cannot absorb the same quantity of oil contained in full fat soy flour. The use of the refatted soy flour as a replacement for the full fat soy flour in applicant's copending application does not provide as effective a product as the full fat soy flour product.
It has now been found that an egg yolk replacer can be prepared from defatted soy flour which provides the same beneficial qualities as a similar composition prepared using full fat soy flour.